The present invention relates generally to electrical connectors, and more particularly to electrical connectors which comprise differential signal pairs of electrical contacts that are designed for high speed electronic communication.
Electrical connectors provide signal connections between electronic devices using signal contacts. Often, the signal contacts are so closely spaced that undesirable interference or cross talk can occur between adjacent signal contacts. Cross talk occurs when one signal contact induces electrical interference in an adjacent contact due to the overlapping of electrical fields, thereby compromising signal integrity. With electronic device miniaturization and high speed electronic communication becoming more prevalent, the reduction of cross talk becomes a significant factor in connector design.
One commonly used technique for reducing cross talk is to position separate electrical shields, in the form of metallic plates, for example, between adjacent signal contacts. The shields act to block cross talk between the signal contacts by eliminating the overlapping electrical fields. Shields, however, take up valuable space within the connector that could otherwise be used to provide additional signal contacts, and thus limit contact density and connector size. Shields also increase the cost of manufacture of the connector.
While it is known to use air gaps between signal contacts to enhance electrical isolation of adjacent contacts, the utilization of air gaps can: compromise the structural integrity of the connector or complicate the design of the connector by requiring a multiplicity of terminal supporting frames or wafers, as well as increase the physical size of the connector. In pin headers of backplane connectors, for example, it is desirable that the connector housing have a one-piece plastic design that will withstand significant forces during insertion of a daughter card connector into engaging relation with the multiplicity of pin header contacts. There is a need to improve electrical signal integrity in such pin header connectors consistent with signal integrity achieved by daughter card connectors which employ a plurality of separate signal contact-carrying wafers.